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8 Reasons Why WhatsApp Was Able to Support 50 Billion Messages a Day With Only 32 Engineers
(newsletter.systemdesign.one)
This is a most excellent place for technology news and articles.
I like how "Don't reinvent the wheel" is almost immediately followed by "they rewrote some of the core components to fit their needs". Isn't that basically reinventing the wheel with a few extra steps?
More a redesign the wheel.